How to set up 90mmDBW motor, actuating two 4 barrel throttle bodies?

[GrannySShifting]

each throttle bore is 1.712" diameter I believe the measurement is, when calcing area for the ETC scaler I ended up with something like 10,700 I believe. Highside hardcode limit is 8191 so tried putting it there, and then taking the difference out of idle airflow ECT mult, but that doesnt affect the closed TPS position calcs or anything

the TB does a "self check" it seems where it runs motor towards the closed position and then back to rest position. We had to have the butterflies pretty far open to give it enough range to run shut and not stop and code out before it even starts up. Which makes it start and idle high as HELL, and it only wants to close the blades down to whatever it thinks 12% throttle is, I zeroed out ALL airflo tables and minimums I could find just to get it there, set the effective area max fail from 200 to 20 even to bring it down

Anyone set something like this up before?

2014 Chevy SS cop car, Mad Max style LOL, 8-71 blower, injectors mounted on top the blower, lot of fun this will be LOL

[GrannySShifting]

Original file and base flash

BaseSD2=self flared log

[schpenxel]

I want to see some pictures of this thing

[GrannySShifting]

Anyone have any experience doing anything like this?

[GHuggins]

I've got some experience with a 108 throttle body attached to a pd blower, but nothing this crazy This sounds interesting... Was wondering if your tune was scaled any? Looks like it is... Make sure your scaling everything with g/s in it. Lots of tables... Such as your min air. Not sure if that one's scaled? Then all of your idle proportional and integral tables. Basically just all airflow tables with g/s. That will effect how high it's trying to idle a lot. Ran into the same problem when I screwed up a scaled tune... I wonder if your idling at a commanded 14.7 a/f or possibly a 14.1ish to 13.9ish a/f in closed loop? I know when I screwed up scaling it was running around that.

After scaling's fixed you can also go to throttle follower torque and dial down the lower rpm areas to help bring it down a little, but I'm willing to bet it's just in the scaling of the tables.

Definitely would like to see pics

[GrannySShifting]

Definitely would like to see pics

Im thinking I need to do the math for blade surface area of 2 barrels each not four, since its prog linkage and the secondaries shouldnt be opened up in the lower TPS ranges too..

One bore= 2.3" surface area. 4 of them (two primaries per TB) = 9.2"/(12.56" of 4" TB blade area) leaves me with .73 * original scaler value of 5636ish right?

[GHuggins]

Anyone can correct if I'm wrong on this, but it's been my experience that the smaller the etc scaler, the slower it will try to close, but on the upside it will also cause quicker throttle openings. I would think in your case you might want it maxed at 81whatever... I know if the tune isn't scaled right, which some things I saw in this one wasn't (could be wrong - mind posting stock tune?) it will exhibit the very same problems your having. Been there, done that All idle proportional and basically anything with g/s needs to be scaled to whatever your scaling yours at. At that time you can take the torque follower tables and min airflow tables and dial back in your throttle closing...

[GrannySShifting]

Anyone can correct if I'm wrong on this, but it's been my experience that the smaller the etc scaler, the slower it will try to close, but on the upside it will also cause quicker throttle openings. I would think in your case you might want it maxed at 81whatever... I know if the tune isn't scaled right, which some things I saw in this one wasn't (could be wrong - mind posting stock tune?) it will exhibit the very same problems your having. Been there, done that All idle proportional and basically anything with g/s needs to be scaled to whatever your scaling yours at. At that time you can take the torque follower tables and min airflow tables and dial back in your throttle closing...

here with Scalar value for 2 barrels operating at idle (just running off one 4bbl) and all four primary barrels operating

[5FDP]

Pretty neat caprice build.

[GHuggins]

I'm sorry, but I think you might still be shooting yourself in the foot doing it this way. Yes having lower throttle etc scaler values has it's benefits. Trust me it's got them... BUT I say this only because when those last 4 barrels come into the equation it's going to throw all of your transient and wot fueling way off... You'll have to compensate with multiple adjustments to fix all of the induced "bugs". Your min airflow values are still WAY to high or at least appear to be? (800rpms = 12g/s then on up to 7000 where you've set it to 66g/s). Your throttle follower torque table appears to be way too low (-22lb/ft at 7000? then dwindles down less and less from there?). There's still quite a few g/s tables not halved correctly. I learned the very hard way that if you scale for injectors, timing and boost like your trying to do, it all MUST be right or very bad things like lifting the heads off the motor can happen This is why I now tune the higher hp builds with pressure gauges teed into the cooling system and all sorts of scopes hooked up... All of these I believe would better address the throttle not closing problem your experiencing.

Engine definitely looks cool. Hope your able to get it sorted without incident...

[GrannySShifting]

I'm sorry, but I think you might still be shooting yourself in the foot doing it this way. Yes having lower throttle etc scaler values has it's benefits. Trust me it's got them... BUT I say this only because when those last 4 barrels come into the equation it's going to throw all of your transient and wot fueling way off... You'll have to compensate with multiple adjustments to fix all of the induced "bugs". Your min airflow values are still WAY to high or at least appear to be? (800rpms = 12g/s then on up to 7000 where you've set it to 66g/s). Your throttle follower torque table appears to be way too low (-22lb/ft at 7000? then dwindles down less and less from there?). There's still quite a few g/s tables not halved correctly. I learned the very hard way that if you scale for injectors, timing and boost like your trying to do, it all MUST be right or very bad things like lifting the heads off the motor can happen This is why I now tune the higher hp builds with pressure gauges teed into the cooling system and all sorts of scopes hooked up... All of these I believe would better address the throttle not closing problem your experiencing.

Engine definitely looks cool. Hope your able to get it sorted without incident...

What scaling are you talking about? The only thing changed was the raw scalar value itself. Going from say a stock TB to NW 102 thats all Ive ever changed and the rest of the base running airflow startup airflow etc tables worked pretty close from there with just some tweaking... Not like inj scaling where you cant put 160# in so you put in 8 and then half all the other tables related. What do you recommend to wrangle this thing out? I would have put two stock TB on it facing upward, used tthe available harness and been done with it if I was involved in any of the decision making up until the point of trying to fire it up LOL

I wish you could see the math the PCM was doing in the background so you could see the areas getting added up in all the different tables and see it get translated into a TPS value instead of guess work

[GHuggins]

I don't have a stock caprice tune in front of me. From what I can see you've got different injectors and have scaled your ignition timing main tables. Haven't looked into it really deep, just thought with the blower and the fact that the ignition tables appear to be scaled that you also were scaling your corresponding air tables? Could be wrong with this of course... Guess it depends on which injectors your using and whether or not you had to scale them any to input the data??? I was figuring with this setup you would be using something like ID 2000's which would require scaling everything. Anything under that and you can typically use the half injector double stoich trick.

Could we possibly get a full build info list and stock ecm calibration file?
Thanks

[GrannySShifting]

Stock file

Tell you the truth not sure exactly what inj are in it, told they were 90# something, look like Deka 80s to me. Small enough that should be able to get it to run even with inj data off *a little*

Bone stock motor with headers, and this dumb blower contraption and TBs on top of it. Inj are ABOVE the blower rotors. Interesting

Throttle follower torque tables etc are stock. Timing not scaled, just limited at 8 degrees everywhere under any load because this thing will make so much torque off idle I wanted to start LOWWWW. Wont be able to kill enough torque with this thing to use any of it, hes just going for the MadMax look

[GHuggins]

OK, this is why it pays to have a stock file for comparison and more info Otherwise with what little I was looking at it almost looked like a scaled tune. ODD that they went with 80's? Another reason I though it had been scaled. Thought it would need bigger injectors... Sounds like someone's trying to top fuel it? Or rather do it like the top fuelers do and run injectors everywhere. I can understand going in the top with one of these for compressor cooling. These are the most inefficient blowers made... Otherwise that's a lot of money to put into something just for looks?

[GrannySShifting]

OK, this is why it pays to have a stock file for comparison and more info Otherwise with what little I was looking at it almost looked like a scaled tune. ODD that they went with 80's? Another reason I though it had been scaled. Thought it would need bigger injectors... Sounds like someone's trying to top fuel it? Or rather do it like the top fuelers do and run injectors everywhere. I can understand going in the top with one of these for compressor cooling. These are the most inefficient blowers made... Otherwise that's a lot of money to put into something just for looks?

Yes this thing is an exorcise in futility LOL

[GrannySShifting]

OK, this is why it pays to have a stock file for comparison and more info Otherwise with what little I was looking at it almost looked like a scaled tune. ODD that they went with 80's? Another reason I though it had been scaled. Thought it would need bigger injectors... Sounds like someone's trying to top fuel it? Or rather do it like the top fuelers do and run injectors everywhere. I can understand going in the top with one of these for compressor cooling. These are the most inefficient blowers made... Otherwise that's a lot of money to put into something just for looks?

So do you have any ideas starting from stock file what would be needed to get this thing to cooperate? Im fresh out of things to try

[GHuggins]

I'm wondering if it's a tune issue at all? Really stupid question at this point, but is it using the original electronic motor setup and is it "geared" 1:1 through the linkage setup? Sounds more like somethings off in the linkage since it had to have the plates opened "way" up to keep it from failing during it's sweep.

Only other things I can think of since it's startup related is start up airflow - especially since that's all way off now and then otherwise performing a GM scanner TB relearn?

[GHuggins]

Just checked. Startup airflow's still stock. Guess you could try multiplying it by .5 and seeing what happens if you haven't all ready tried that?

[Rocko350]

I have worked on vehicle that needed the TB cleaned after I finished a log and found the idle minimum % for airflow was at 21%. This was on a 4.8l half ton pickup lifted with huge tires. Cleaned the TB, reset minimum idle air with scan tool. Don't think the VCM has this built in. Then the guys truck would start properly. It helped with a lean snap and occasional code after reflash. You might need to have this done so you can tune the idle correctly. Also remember the time to get fuel into the chamber is much longer now. I'd bet the extended cranking time makes it run rich as h e double hockey sticks on first fireoff an it chases its tail until the air column stabilizes.

Chris

[blownbluez06]

I see values in the follower, cooling fan and many other items which might be adding to it. Not sure, but I would zero them all out for gits and shiggles.